Biggest ****mers. Payment for the month while I didnt have access to the internet

My debit order goes off on the 15th of each month. I cancelled my subscription in November and got confirmation of cancellation on the 08th November 2025 and my account was debited on the 15th November 2025. On the 15th December 2025 I still get debited. Why if from the 01st December I did not have access, then why am I still debited? The explanation from the consultant is that I am paying for 15th-30 November since I still had access, then why is it the full amount? They say no contract obligations yet there are riping people off.